Its not common knowledge, but I long suspected that they are the reason for so many attempts to shut down national and state parks.
Park Rangers are armed and better trained than cops. They know crazy amounts of wilderness survival. And unlike cops, be it local, state, or federal, they have an interest in protecting something rather than power tripping.
But far, far, far more advantageous is that a surprising number of them can navigate entire parks (with exceptions). The national park system has like 80-90million acres (about the total size of Finland or Germany).
The reason I don't think many really think about it is because they're pretty small in number. Like 1300 or so nation wide. But, the National Park Service has 20k employees, and nearly 400,000 volunteers. They certainly aren't going anywhere.